libavcodec/mpeg12enc.c

Go to the documentation of this file.

/*
 * MPEG1/2 encoder
 * Copyright (c) 2000,2001 Fabrice Bellard
 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "avcodec.h"
#include "dsputil.h"
#include "mathops.h"
#include "mpegvideo.h"

#include "mpeg12.h"
#include "mpeg12data.h"
#include "bytestream.h"
#include "libavutil/log.h"
#include "libavutil/opt.h"
#include "libavutil/avassert.h"
#include "libavutil/timecode.h"

static const uint8_t inv_non_linear_qscale[13] = {
    0, 2, 4, 6, 8,
    9,10,11,12,13,14,15,16,
};

static const uint8_t svcd_scan_offset_placeholder[14] = {
    0x10, 0x0E,
    0x00, 0x80, 0x81,
    0x00, 0x80, 0x81,
    0xff, 0xff, 0xff,
    0xff, 0xff, 0xff,
};

static void mpeg1_encode_block(MpegEncContext *s,
                         DCTELEM *block,
                         int component);
static void mpeg1_encode_motion(MpegEncContext *s, int val, int f_or_b_code);    // RAL: f_code parameter added

static uint8_t mv_penalty[MAX_FCODE+1][MAX_MV*2+1];
static uint8_t fcode_tab[MAX_MV*2+1];

static uint8_t  uni_mpeg1_ac_vlc_len [64*64*2];
static uint8_t  uni_mpeg2_ac_vlc_len [64*64*2];

/* simple include everything table for dc, first byte is bits number next 3 are code*/
static uint32_t mpeg1_lum_dc_uni[512];
static uint32_t mpeg1_chr_dc_uni[512];

static uint8_t mpeg1_index_run[2][64];
static int8_t mpeg1_max_level[2][64];

static void init_uni_ac_vlc(RLTable *rl, uint8_t *uni_ac_vlc_len){
    int i;

    for(i=0; i<128; i++){
        int level= i-64;
        int run;
        if (!level)
            continue;
        for(run=0; run<64; run++){
            int len, code;

            int alevel= FFABS(level);

            if (alevel > rl->max_level[0][run])
                code= 111; /*rl->n*/
            else
                code= rl->index_run[0][run] + alevel - 1;

            if (code < 111 /* rl->n */) {
                /* length of vlc and sign */
                len=   rl->table_vlc[code][1]+1;
            } else {
                len=  rl->table_vlc[111/*rl->n*/][1]+6;

                if (alevel < 128) {
                    len += 8;
                } else {
                    len += 16;
                }
            }

            uni_ac_vlc_len [UNI_AC_ENC_INDEX(run, i)]= len;
        }
    }
}


static int find_frame_rate_index(MpegEncContext *s){
    int i;
    int64_t dmin= INT64_MAX;
    int64_t d;

    for(i=1;i<14;i++) {
        int64_t n0= 1001LL/avpriv_frame_rate_tab[i].den*avpriv_frame_rate_tab[i].num*s->avctx->time_base.num;
        int64_t n1= 1001LL*s->avctx->time_base.den;
        if(s->avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL && i>=9) break;

        d = FFABS(n0 - n1);
        if(d < dmin){
            dmin=d;
            s->frame_rate_index= i;
        }
    }
    if(dmin)
        return -1;
    else
        return 0;
}

static av_cold int encode_init(AVCodecContext *avctx)
{
    MpegEncContext *s = avctx->priv_data;

    if(ff_MPV_encode_init(avctx) < 0)
        return -1;

    if(find_frame_rate_index(s) < 0){
        if(s->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL){
            av_log(avctx, AV_LOG_ERROR, "MPEG1/2 does not support %d/%d fps\n", avctx->time_base.den, avctx->time_base.num);
            return -1;
        }else{
            av_log(avctx, AV_LOG_INFO, "MPEG1/2 does not support %d/%d fps, there may be AV sync issues\n", avctx->time_base.den, avctx->time_base.num);
        }
    }

    if(avctx->profile == FF_PROFILE_UNKNOWN){
        if(avctx->level != FF_LEVEL_UNKNOWN){
            av_log(avctx, AV_LOG_ERROR, "Set profile and level\n");
            return -1;
        }
        avctx->profile = s->chroma_format == CHROMA_420 ? 4 : 0; /* Main or 4:2:2 */
    }

    if(avctx->level == FF_LEVEL_UNKNOWN){
        if(avctx->profile == 0){ /* 4:2:2 */
            if(avctx->width <= 720 && avctx->height <= 608) avctx->level = 5; /* Main */
            else                                            avctx->level = 2; /* High */
        }else{
            if(avctx->profile != 1 && s->chroma_format != CHROMA_420){
                av_log(avctx, AV_LOG_ERROR, "Only High(1) and 4:2:2(0) profiles support 4:2:2 color sampling\n");
                return -1;
            }
            if(avctx->width <= 720 && avctx->height <= 576) avctx->level = 8; /* Main */
            else if(avctx->width <= 1440)                   avctx->level = 6; /* High 1440 */
            else                                            avctx->level = 4; /* High */
        }
    }

    s->drop_frame_timecode = s->drop_frame_timecode || !!(avctx->flags2 & CODEC_FLAG2_DROP_FRAME_TIMECODE);
    if (s->drop_frame_timecode)
        s->tc.flags |= AV_TIMECODE_FLAG_DROPFRAME;
    if (s->drop_frame_timecode && s->frame_rate_index != 4) {
        av_log(avctx, AV_LOG_ERROR, "Drop frame time code only allowed with 1001/30000 fps\n");
        return -1;
    }

    if (s->tc_opt_str) {
        AVRational rate = avpriv_frame_rate_tab[s->frame_rate_index];
        int ret = av_timecode_init_from_string(&s->tc, rate, s->tc_opt_str, s);
        if (ret < 0)
            return ret;
        s->drop_frame_timecode = !!(s->tc.flags & AV_TIMECODE_FLAG_DROPFRAME);
        s->avctx->timecode_frame_start = s->tc.start;
    } else {
        s->avctx->timecode_frame_start = 0; // default is -1
    }
    return 0;
}

static void put_header(MpegEncContext *s, int header)
{
    avpriv_align_put_bits(&s->pb);
    put_bits(&s->pb, 16, header>>16);
    put_sbits(&s->pb, 16, header);
}

/* put sequence header if needed */
static void mpeg1_encode_sequence_header(MpegEncContext *s)
{
        unsigned int vbv_buffer_size;
        unsigned int fps, v;
        int i;
        uint64_t time_code;
        float best_aspect_error= 1E10;
        float aspect_ratio= av_q2d(s->avctx->sample_aspect_ratio);
        int constraint_parameter_flag;

        if(aspect_ratio==0.0) aspect_ratio= 1.0; //pixel aspect 1:1 (VGA)

        if (s->current_picture.f.key_frame) {
            AVRational framerate= avpriv_frame_rate_tab[s->frame_rate_index];

            /* mpeg1 header repeated every gop */
            put_header(s, SEQ_START_CODE);

            put_sbits(&s->pb, 12, s->width );
            put_sbits(&s->pb, 12, s->height);

            for(i=1; i<15; i++){
                float error= aspect_ratio;
                if(s->codec_id == CODEC_ID_MPEG1VIDEO || i <=1)
                    error-= 1.0/ff_mpeg1_aspect[i];
                else
                    error-= av_q2d(ff_mpeg2_aspect[i])*s->height/s->width;

                error= FFABS(error);

                if(error < best_aspect_error){
                    best_aspect_error= error;
                    s->aspect_ratio_info= i;
                }
            }

            put_bits(&s->pb, 4, s->aspect_ratio_info);
            put_bits(&s->pb, 4, s->frame_rate_index);

            if(s->avctx->rc_max_rate){
                v = (s->avctx->rc_max_rate + 399) / 400;
                if (v > 0x3ffff && s->codec_id == CODEC_ID_MPEG1VIDEO)
                    v = 0x3ffff;
            }else{
                v= 0x3FFFF;
            }

            if(s->avctx->rc_buffer_size)
                vbv_buffer_size = s->avctx->rc_buffer_size;
            else
                /* VBV calculation: Scaled so that a VCD has the proper VBV size of 40 kilobytes */
                vbv_buffer_size = (( 20 * s->bit_rate) / (1151929 / 2)) * 8 * 1024;
            vbv_buffer_size= (vbv_buffer_size + 16383) / 16384;

            put_sbits(&s->pb, 18, v);
            put_bits(&s->pb, 1, 1); /* marker */
            put_sbits(&s->pb, 10, vbv_buffer_size);

            constraint_parameter_flag=
                s->width <= 768 && s->height <= 576 &&
                s->mb_width * s->mb_height <= 396 &&
                s->mb_width * s->mb_height * framerate.num <= framerate.den*396*25 &&
                framerate.num <= framerate.den*30 &&
                s->avctx->me_range && s->avctx->me_range < 128 &&
                vbv_buffer_size <= 20 &&
                v <= 1856000/400 &&
                s->codec_id == CODEC_ID_MPEG1VIDEO;

            put_bits(&s->pb, 1, constraint_parameter_flag);

            ff_write_quant_matrix(&s->pb, s->avctx->intra_matrix);
            ff_write_quant_matrix(&s->pb, s->avctx->inter_matrix);

            if(s->codec_id == CODEC_ID_MPEG2VIDEO){
                put_header(s, EXT_START_CODE);
                put_bits(&s->pb, 4, 1); //seq ext

                put_bits(&s->pb, 1, s->avctx->profile == 0); //escx 1 for 4:2:2 profile */

                put_bits(&s->pb, 3, s->avctx->profile); //profile
                put_bits(&s->pb, 4, s->avctx->level); //level

                put_bits(&s->pb, 1, s->progressive_sequence);
                put_bits(&s->pb, 2, s->chroma_format);
                put_bits(&s->pb, 2, s->width >>12);
                put_bits(&s->pb, 2, s->height>>12);
                put_bits(&s->pb, 12, v>>18); //bitrate ext
                put_bits(&s->pb, 1, 1); //marker
                put_bits(&s->pb, 8, vbv_buffer_size >>10); //vbv buffer ext
                put_bits(&s->pb, 1, s->low_delay);
                put_bits(&s->pb, 2, 0); // frame_rate_ext_n
                put_bits(&s->pb, 5, 0); // frame_rate_ext_d
            }

            put_header(s, GOP_START_CODE);
            put_bits(&s->pb, 1, s->drop_frame_timecode); /* drop frame flag */
            /* time code : we must convert from the real frame rate to a
               fake mpeg frame rate in case of low frame rate */
            fps = (framerate.num + framerate.den/2)/ framerate.den;
            time_code = s->current_picture_ptr->f.coded_picture_number + s->avctx->timecode_frame_start;

            s->gop_picture_number = s->current_picture_ptr->f.coded_picture_number;
            av_assert0(s->drop_frame_timecode == !!(s->tc.flags & AV_TIMECODE_FLAG_DROPFRAME));
            if (s->drop_frame_timecode)
                time_code = av_timecode_adjust_ntsc_framenum(time_code);
            put_bits(&s->pb, 5, (uint32_t)((time_code / (fps * 3600)) % 24));
            put_bits(&s->pb, 6, (uint32_t)((time_code / (fps * 60)) % 60));
            put_bits(&s->pb, 1, 1);
            put_bits(&s->pb, 6, (uint32_t)((time_code / fps) % 60));
            put_bits(&s->pb, 6, (uint32_t)((time_code % fps)));
            put_bits(&s->pb, 1, !!(s->flags & CODEC_FLAG_CLOSED_GOP));
            put_bits(&s->pb, 1, 0); /* broken link */
        }
}

static inline void encode_mb_skip_run(MpegEncContext *s, int run){
    while (run >= 33) {
        put_bits(&s->pb, 11, 0x008);
        run -= 33;
    }
    put_bits(&s->pb, ff_mpeg12_mbAddrIncrTable[run][1],
             ff_mpeg12_mbAddrIncrTable[run][0]);
}

static av_always_inline void put_qscale(MpegEncContext *s)
{
    if(s->q_scale_type){
        assert(s->qscale>=1 && s->qscale <=12);
        put_bits(&s->pb, 5, inv_non_linear_qscale[s->qscale]);
    }else{
        put_bits(&s->pb, 5, s->qscale);
    }
}

void ff_mpeg1_encode_slice_header(MpegEncContext *s){
    if (s->codec_id == CODEC_ID_MPEG2VIDEO && s->height > 2800) {
        put_header(s, SLICE_MIN_START_CODE + (s->mb_y & 127));
        put_bits(&s->pb, 3, s->mb_y >> 7);  /* slice_vertical_position_extension */
    } else {
        put_header(s, SLICE_MIN_START_CODE + s->mb_y);
    }
    put_qscale(s);
    put_bits(&s->pb, 1, 0); /* slice extra information */
}

void ff_mpeg1_encode_picture_header(MpegEncContext *s, int picture_number)
{
    mpeg1_encode_sequence_header(s);

    /* mpeg1 picture header */
    put_header(s, PICTURE_START_CODE);
    /* temporal reference */

    // RAL: s->picture_number instead of s->fake_picture_number
    put_bits(&s->pb, 10, (s->picture_number -
                          s->gop_picture_number) & 0x3ff);
    put_bits(&s->pb, 3, s->pict_type);

    s->vbv_delay_ptr= s->pb.buf + put_bits_count(&s->pb)/8;
    put_bits(&s->pb, 16, 0xFFFF); /* vbv_delay */

    // RAL: Forward f_code also needed for B frames
    if (s->pict_type == AV_PICTURE_TYPE_P || s->pict_type == AV_PICTURE_TYPE_B) {
        put_bits(&s->pb, 1, 0); /* half pel coordinates */
        if(s->codec_id == CODEC_ID_MPEG1VIDEO)
            put_bits(&s->pb, 3, s->f_code); /* forward_f_code */
        else
            put_bits(&s->pb, 3, 7); /* forward_f_code */
    }

    // RAL: Backward f_code necessary for B frames
    if (s->pict_type == AV_PICTURE_TYPE_B) {
        put_bits(&s->pb, 1, 0); /* half pel coordinates */
        if(s->codec_id == CODEC_ID_MPEG1VIDEO)
            put_bits(&s->pb, 3, s->b_code); /* backward_f_code */
        else
            put_bits(&s->pb, 3, 7); /* backward_f_code */
    }

    put_bits(&s->pb, 1, 0); /* extra bit picture */

    s->frame_pred_frame_dct = 1;
    if(s->codec_id == CODEC_ID_MPEG2VIDEO){
        put_header(s, EXT_START_CODE);
        put_bits(&s->pb, 4, 8); //pic ext
        if (s->pict_type == AV_PICTURE_TYPE_P || s->pict_type == AV_PICTURE_TYPE_B) {
            put_bits(&s->pb, 4, s->f_code);
            put_bits(&s->pb, 4, s->f_code);
        }else{
            put_bits(&s->pb, 8, 255);
        }
        if (s->pict_type == AV_PICTURE_TYPE_B) {
            put_bits(&s->pb, 4, s->b_code);
            put_bits(&s->pb, 4, s->b_code);
        }else{
            put_bits(&s->pb, 8, 255);
        }
        put_bits(&s->pb, 2, s->intra_dc_precision);

        assert(s->picture_structure == PICT_FRAME);
        put_bits(&s->pb, 2, s->picture_structure);
        if (s->progressive_sequence) {
            put_bits(&s->pb, 1, 0); /* no repeat */
        } else {
            put_bits(&s->pb, 1, s->current_picture_ptr->f.top_field_first);
        }
        /* XXX: optimize the generation of this flag with entropy
           measures */
        s->frame_pred_frame_dct = s->progressive_sequence;

        put_bits(&s->pb, 1, s->frame_pred_frame_dct);
        put_bits(&s->pb, 1, s->concealment_motion_vectors);
        put_bits(&s->pb, 1, s->q_scale_type);
        put_bits(&s->pb, 1, s->intra_vlc_format);
        put_bits(&s->pb, 1, s->alternate_scan);
        put_bits(&s->pb, 1, s->repeat_first_field);
        s->progressive_frame = s->progressive_sequence;
        put_bits(&s->pb, 1, s->chroma_format == CHROMA_420 ? s->progressive_frame : 0); /* chroma_420_type */
        put_bits(&s->pb, 1, s->progressive_frame);
        put_bits(&s->pb, 1, 0); //composite_display_flag
    }
    if (s->scan_offset) {
        int i;

        put_header(s, USER_START_CODE);
        for(i=0; i<sizeof(svcd_scan_offset_placeholder); i++){
            put_bits(&s->pb, 8, svcd_scan_offset_placeholder[i]);
        }
    }

    s->mb_y=0;
    ff_mpeg1_encode_slice_header(s);
}

static inline void put_mb_modes(MpegEncContext *s, int n, int bits,
                                int has_mv, int field_motion)
{
    put_bits(&s->pb, n, bits);
    if (!s->frame_pred_frame_dct) {
        if (has_mv)
            put_bits(&s->pb, 2, 2 - field_motion); /* motion_type: frame/field */
        put_bits(&s->pb, 1, s->interlaced_dct);
    }
}

static av_always_inline void mpeg1_encode_mb_internal(MpegEncContext *s,
                                                   DCTELEM block[6][64],
                                                   int motion_x, int motion_y,
                                                   int mb_block_count)
{
    int i, cbp;
    const int mb_x = s->mb_x;
    const int mb_y = s->mb_y;
    const int first_mb= mb_x == s->resync_mb_x && mb_y == s->resync_mb_y;

    /* compute cbp */
    cbp = 0;
    for(i=0;i<mb_block_count;i++) {
        if (s->block_last_index[i] >= 0)
            cbp |= 1 << (mb_block_count - 1 - i);
    }

    if (cbp == 0 && !first_mb && s->mv_type == MV_TYPE_16X16 &&
        (mb_x != s->mb_width - 1 || (mb_y != s->mb_height - 1 && s->codec_id == CODEC_ID_MPEG1VIDEO)) &&
        ((s->pict_type == AV_PICTURE_TYPE_P && (motion_x | motion_y) == 0) ||
        (s->pict_type == AV_PICTURE_TYPE_B && s->mv_dir == s->last_mv_dir && (((s->mv_dir & MV_DIR_FORWARD) ? ((s->mv[0][0][0] - s->last_mv[0][0][0])|(s->mv[0][0][1] - s->last_mv[0][0][1])) : 0) |
        ((s->mv_dir & MV_DIR_BACKWARD) ? ((s->mv[1][0][0] - s->last_mv[1][0][0])|(s->mv[1][0][1] - s->last_mv[1][0][1])) : 0)) == 0))) {
        s->mb_skip_run++;
        s->qscale -= s->dquant;
        s->skip_count++;
        s->misc_bits++;
        s->last_bits++;
        if(s->pict_type == AV_PICTURE_TYPE_P){
            s->last_mv[0][1][0]= s->last_mv[0][0][0]=
            s->last_mv[0][1][1]= s->last_mv[0][0][1]= 0;
        }
    } else {
        if(first_mb){
            assert(s->mb_skip_run == 0);
            encode_mb_skip_run(s, s->mb_x);
        }else{
            encode_mb_skip_run(s, s->mb_skip_run);
        }

        if (s->pict_type == AV_PICTURE_TYPE_I) {
            if(s->dquant && cbp){
                put_mb_modes(s, 2, 1, 0, 0); /* macroblock_type : macroblock_quant = 1 */
                put_qscale(s);
            }else{
                put_mb_modes(s, 1, 1, 0, 0); /* macroblock_type : macroblock_quant = 0 */
                s->qscale -= s->dquant;
            }
            s->misc_bits+= get_bits_diff(s);
            s->i_count++;
        } else if (s->mb_intra) {
            if(s->dquant && cbp){
                put_mb_modes(s, 6, 0x01, 0, 0);
                put_qscale(s);
            }else{
                put_mb_modes(s, 5, 0x03, 0, 0);
                s->qscale -= s->dquant;
            }
            s->misc_bits+= get_bits_diff(s);
            s->i_count++;
            memset(s->last_mv, 0, sizeof(s->last_mv));
        } else if (s->pict_type == AV_PICTURE_TYPE_P) {
            if(s->mv_type == MV_TYPE_16X16){
                if (cbp != 0) {
                    if ((motion_x|motion_y) == 0) {
                        if(s->dquant){
                            put_mb_modes(s, 5, 1, 0, 0); /* macroblock_pattern & quant */
                            put_qscale(s);
                        }else{
                            put_mb_modes(s, 2, 1, 0, 0); /* macroblock_pattern only */
                        }
                        s->misc_bits+= get_bits_diff(s);
                    } else {
                        if(s->dquant){
                            put_mb_modes(s, 5, 2, 1, 0); /* motion + cbp */
                            put_qscale(s);
                        }else{
                            put_mb_modes(s, 1, 1, 1, 0); /* motion + cbp */
                        }
                        s->misc_bits+= get_bits_diff(s);
                        mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code);    // RAL: f_code parameter added
                        mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code);    // RAL: f_code parameter added
                        s->mv_bits+= get_bits_diff(s);
                    }
                } else {
                    put_bits(&s->pb, 3, 1); /* motion only */
                    if (!s->frame_pred_frame_dct)
                        put_bits(&s->pb, 2, 2); /* motion_type: frame */
                    s->misc_bits+= get_bits_diff(s);
                    mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code);    // RAL: f_code parameter added
                    mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code);    // RAL: f_code parameter added
                    s->qscale -= s->dquant;
                    s->mv_bits+= get_bits_diff(s);
                }
                s->last_mv[0][1][0]= s->last_mv[0][0][0]= motion_x;
                s->last_mv[0][1][1]= s->last_mv[0][0][1]= motion_y;
            }else{
                assert(!s->frame_pred_frame_dct && s->mv_type == MV_TYPE_FIELD);

                if (cbp) {
                    if(s->dquant){
                        put_mb_modes(s, 5, 2, 1, 1); /* motion + cbp */
                        put_qscale(s);
                    }else{
                        put_mb_modes(s, 1, 1, 1, 1); /* motion + cbp */
                    }
                } else {
                    put_bits(&s->pb, 3, 1); /* motion only */
                    put_bits(&s->pb, 2, 1); /* motion_type: field */
                    s->qscale -= s->dquant;
                }
                s->misc_bits+= get_bits_diff(s);
                for(i=0; i<2; i++){
                    put_bits(&s->pb, 1, s->field_select[0][i]);
                    mpeg1_encode_motion(s, s->mv[0][i][0] -  s->last_mv[0][i][0]    , s->f_code);
                    mpeg1_encode_motion(s, s->mv[0][i][1] - (s->last_mv[0][i][1]>>1), s->f_code);
                    s->last_mv[0][i][0]=   s->mv[0][i][0];
                    s->last_mv[0][i][1]= 2*s->mv[0][i][1];
                }
                s->mv_bits+= get_bits_diff(s);
            }
            if(cbp) {
                if (s->chroma_y_shift) {
                    put_bits(&s->pb, ff_mpeg12_mbPatTable[cbp][1], ff_mpeg12_mbPatTable[cbp][0]);
                } else {
                    put_bits(&s->pb, ff_mpeg12_mbPatTable[cbp>>2][1], ff_mpeg12_mbPatTable[cbp>>2][0]);
                    put_sbits(&s->pb, 2, cbp);
                }
            }
            s->f_count++;
        } else{
            if(s->mv_type == MV_TYPE_16X16){
                if (cbp){    // With coded bloc pattern
                    if (s->dquant) {
                        if(s->mv_dir == MV_DIR_FORWARD)
                            put_mb_modes(s, 6, 3, 1, 0);
                        else
                            put_mb_modes(s, 8-s->mv_dir, 2, 1, 0);
                        put_qscale(s);
                    } else {
                        put_mb_modes(s, 5-s->mv_dir, 3, 1, 0);
                    }
                }else{    // No coded bloc pattern
                    put_bits(&s->pb, 5-s->mv_dir, 2);
                    if (!s->frame_pred_frame_dct)
                        put_bits(&s->pb, 2, 2); /* motion_type: frame */
                    s->qscale -= s->dquant;
                }
                s->misc_bits += get_bits_diff(s);
                if (s->mv_dir&MV_DIR_FORWARD){
                    mpeg1_encode_motion(s, s->mv[0][0][0] - s->last_mv[0][0][0], s->f_code);
                    mpeg1_encode_motion(s, s->mv[0][0][1] - s->last_mv[0][0][1], s->f_code);
                    s->last_mv[0][0][0]=s->last_mv[0][1][0]= s->mv[0][0][0];
                    s->last_mv[0][0][1]=s->last_mv[0][1][1]= s->mv[0][0][1];
                    s->f_count++;
                }
                if (s->mv_dir&MV_DIR_BACKWARD){
                    mpeg1_encode_motion(s, s->mv[1][0][0] - s->last_mv[1][0][0], s->b_code);
                    mpeg1_encode_motion(s, s->mv[1][0][1] - s->last_mv[1][0][1], s->b_code);
                    s->last_mv[1][0][0]=s->last_mv[1][1][0]= s->mv[1][0][0];
                    s->last_mv[1][0][1]=s->last_mv[1][1][1]= s->mv[1][0][1];
                    s->b_count++;
                }
            }else{
                assert(s->mv_type == MV_TYPE_FIELD);
                assert(!s->frame_pred_frame_dct);
                if (cbp){    // With coded bloc pattern
                    if (s->dquant) {
                        if(s->mv_dir == MV_DIR_FORWARD)
                            put_mb_modes(s, 6, 3, 1, 1);
                        else
                            put_mb_modes(s, 8-s->mv_dir, 2, 1, 1);
                        put_qscale(s);
                    } else {
                        put_mb_modes(s, 5-s->mv_dir, 3, 1, 1);
                    }
                }else{    // No coded bloc pattern
                    put_bits(&s->pb, 5-s->mv_dir, 2);
                    put_bits(&s->pb, 2, 1); /* motion_type: field */
                    s->qscale -= s->dquant;
                }
                s->misc_bits += get_bits_diff(s);
                if (s->mv_dir&MV_DIR_FORWARD){
                    for(i=0; i<2; i++){
                        put_bits(&s->pb, 1, s->field_select[0][i]);
                        mpeg1_encode_motion(s, s->mv[0][i][0] -  s->last_mv[0][i][0]    , s->f_code);
                        mpeg1_encode_motion(s, s->mv[0][i][1] - (s->last_mv[0][i][1]>>1), s->f_code);
                        s->last_mv[0][i][0]=   s->mv[0][i][0];
                        s->last_mv[0][i][1]= 2*s->mv[0][i][1];
                    }
                    s->f_count++;
                }
                if (s->mv_dir&MV_DIR_BACKWARD){
                    for(i=0; i<2; i++){
                        put_bits(&s->pb, 1, s->field_select[1][i]);
                        mpeg1_encode_motion(s, s->mv[1][i][0] -  s->last_mv[1][i][0]    , s->b_code);
                        mpeg1_encode_motion(s, s->mv[1][i][1] - (s->last_mv[1][i][1]>>1), s->b_code);
                        s->last_mv[1][i][0]=   s->mv[1][i][0];
                        s->last_mv[1][i][1]= 2*s->mv[1][i][1];
                    }
                    s->b_count++;
                }
            }
            s->mv_bits += get_bits_diff(s);
            if(cbp) {
                if (s->chroma_y_shift) {
                    put_bits(&s->pb, ff_mpeg12_mbPatTable[cbp][1], ff_mpeg12_mbPatTable[cbp][0]);
                } else {
                    put_bits(&s->pb, ff_mpeg12_mbPatTable[cbp>>2][1], ff_mpeg12_mbPatTable[cbp>>2][0]);
                    put_sbits(&s->pb, 2, cbp);
                }
            }
        }
        for(i=0;i<mb_block_count;i++) {
            if (cbp & (1 << (mb_block_count - 1 - i))) {
                mpeg1_encode_block(s, block[i], i);
            }
        }
        s->mb_skip_run = 0;
        if(s->mb_intra)
            s->i_tex_bits+= get_bits_diff(s);
        else
            s->p_tex_bits+= get_bits_diff(s);
    }
}

void ff_mpeg1_encode_mb(MpegEncContext *s, DCTELEM block[6][64], int motion_x, int motion_y)
{
    if (s->chroma_format == CHROMA_420) mpeg1_encode_mb_internal(s, block, motion_x, motion_y, 6);
    else                                mpeg1_encode_mb_internal(s, block, motion_x, motion_y, 8);
}

// RAL: Parameter added: f_or_b_code
static void mpeg1_encode_motion(MpegEncContext *s, int val, int f_or_b_code)
{
    if (val == 0) {
        /* zero vector */
        put_bits(&s->pb,
                 ff_mpeg12_mbMotionVectorTable[0][1],
                 ff_mpeg12_mbMotionVectorTable[0][0]);
    } else {
        int code, sign, bits;
        int bit_size = f_or_b_code - 1;
        int range = 1 << bit_size;
        /* modulo encoding */
        val = sign_extend(val, 5 + bit_size);

        if (val >= 0) {
            val--;
            code = (val >> bit_size) + 1;
            bits = val & (range - 1);
            sign = 0;
        } else {
            val = -val;
            val--;
            code = (val >> bit_size) + 1;
            bits = val & (range - 1);
            sign = 1;
        }

        assert(code > 0 && code <= 16);

        put_bits(&s->pb,
                 ff_mpeg12_mbMotionVectorTable[code][1],
                 ff_mpeg12_mbMotionVectorTable[code][0]);

        put_bits(&s->pb, 1, sign);
        if (bit_size > 0) {
            put_bits(&s->pb, bit_size, bits);
        }
    }
}

void ff_mpeg1_encode_init(MpegEncContext *s)
{
    static int done=0;

    ff_mpeg12_common_init(s);

    if(!done){
        int f_code;
        int mv;
        int i;

        done=1;
        ff_init_rl(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]);
        ff_init_rl(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]);

        for(i=0; i<64; i++)
        {
                mpeg1_max_level[0][i]= ff_rl_mpeg1.max_level[0][i];
                mpeg1_index_run[0][i]= ff_rl_mpeg1.index_run[0][i];
        }

        init_uni_ac_vlc(&ff_rl_mpeg1, uni_mpeg1_ac_vlc_len);
        if(s->intra_vlc_format)
            init_uni_ac_vlc(&ff_rl_mpeg2, uni_mpeg2_ac_vlc_len);

        /* build unified dc encoding tables */
        for(i=-255; i<256; i++)
        {
                int adiff, index;
                int bits, code;
                int diff=i;

                adiff = FFABS(diff);
                if(diff<0) diff--;
                index = av_log2(2*adiff);

                bits= ff_mpeg12_vlc_dc_lum_bits[index] + index;
                code= (ff_mpeg12_vlc_dc_lum_code[index]<<index) + (diff & ((1 << index) - 1));
                mpeg1_lum_dc_uni[i+255]= bits + (code<<8);

                bits= ff_mpeg12_vlc_dc_chroma_bits[index] + index;
                code= (ff_mpeg12_vlc_dc_chroma_code[index]<<index) + (diff & ((1 << index) - 1));
                mpeg1_chr_dc_uni[i+255]= bits + (code<<8);
        }

        for(f_code=1; f_code<=MAX_FCODE; f_code++){
            for(mv=-MAX_MV; mv<=MAX_MV; mv++){
                int len;

                if(mv==0) len= ff_mpeg12_mbMotionVectorTable[0][1];
                else{
                    int val, bit_size, code;

                    bit_size = f_code - 1;

                    val=mv;
                    if (val < 0)
                        val = -val;
                    val--;
                    code = (val >> bit_size) + 1;
                    if(code<17){
                        len= ff_mpeg12_mbMotionVectorTable[code][1] + 1 + bit_size;
                    }else{
                        len= ff_mpeg12_mbMotionVectorTable[16][1] + 2 + bit_size;
                    }
                }

                mv_penalty[f_code][mv+MAX_MV]= len;
            }
        }


        for(f_code=MAX_FCODE; f_code>0; f_code--){
            for(mv=-(8<<f_code); mv<(8<<f_code); mv++){
                fcode_tab[mv+MAX_MV]= f_code;
            }
        }
    }
    s->me.mv_penalty= mv_penalty;
    s->fcode_tab= fcode_tab;
    if(s->codec_id == CODEC_ID_MPEG1VIDEO){
        s->min_qcoeff=-255;
        s->max_qcoeff= 255;
    }else{
        s->min_qcoeff=-2047;
        s->max_qcoeff= 2047;
    }
    if (s->intra_vlc_format) {
        s->intra_ac_vlc_length=
        s->intra_ac_vlc_last_length= uni_mpeg2_ac_vlc_len;
    } else {
        s->intra_ac_vlc_length=
        s->intra_ac_vlc_last_length= uni_mpeg1_ac_vlc_len;
    }
    s->inter_ac_vlc_length=
    s->inter_ac_vlc_last_length= uni_mpeg1_ac_vlc_len;
}

static inline void encode_dc(MpegEncContext *s, int diff, int component)
{
  if(((unsigned) (diff+255)) >= 511){
        int index;

        if(diff<0){
            index= av_log2_16bit(-2*diff);
            diff--;
        }else{
            index= av_log2_16bit(2*diff);
        }
        if (component == 0) {
            put_bits(
                &s->pb,
                ff_mpeg12_vlc_dc_lum_bits[index] + index,
                (ff_mpeg12_vlc_dc_lum_code[index]<<index) + (diff & ((1 << index) - 1)));
        }else{
            put_bits(
                &s->pb,
                ff_mpeg12_vlc_dc_chroma_bits[index] + index,
                (ff_mpeg12_vlc_dc_chroma_code[index]<<index) + (diff & ((1 << index) - 1)));
        }
  }else{
    if (component == 0) {
        put_bits(
            &s->pb,
            mpeg1_lum_dc_uni[diff+255]&0xFF,
            mpeg1_lum_dc_uni[diff+255]>>8);
    } else {
        put_bits(
            &s->pb,
            mpeg1_chr_dc_uni[diff+255]&0xFF,
            mpeg1_chr_dc_uni[diff+255]>>8);
    }
  }
}

static void mpeg1_encode_block(MpegEncContext *s,
                               DCTELEM *block,
                               int n)
{
    int alevel, level, last_non_zero, dc, diff, i, j, run, last_index, sign;
    int code, component;
    const uint16_t (*table_vlc)[2] = ff_rl_mpeg1.table_vlc;

    last_index = s->block_last_index[n];

    /* DC coef */
    if (s->mb_intra) {
        component = (n <= 3 ? 0 : (n&1) + 1);
        dc = block[0]; /* overflow is impossible */
        diff = dc - s->last_dc[component];
        encode_dc(s, diff, component);
        s->last_dc[component] = dc;
        i = 1;
        if (s->intra_vlc_format)
            table_vlc = ff_rl_mpeg2.table_vlc;
    } else {
        /* encode the first coefficient : needs to be done here because
           it is handled slightly differently */
        level = block[0];
        if (abs(level) == 1) {
                code = ((uint32_t)level >> 31); /* the sign bit */
                put_bits(&s->pb, 2, code | 0x02);
                i = 1;
        } else {
            i = 0;
            last_non_zero = -1;
            goto next_coef;
        }
    }

    /* now quantify & encode AC coefs */
    last_non_zero = i - 1;

    for(;i<=last_index;i++) {
        j = s->intra_scantable.permutated[i];
        level = block[j];
    next_coef:
        /* encode using VLC */
        if (level != 0) {
            run = i - last_non_zero - 1;

            alevel= level;
            MASK_ABS(sign, alevel)
            sign&=1;

            if (alevel <= mpeg1_max_level[0][run]){
                code= mpeg1_index_run[0][run] + alevel - 1;
                /* store the vlc & sign at once */
                put_bits(&s->pb, table_vlc[code][1]+1, (table_vlc[code][0]<<1) + sign);
            } else {
                /* escape seems to be pretty rare <5% so I do not optimize it */
                put_bits(&s->pb, table_vlc[111][1], table_vlc[111][0]);
                /* escape: only clip in this case */
                put_bits(&s->pb, 6, run);
                if(s->codec_id == CODEC_ID_MPEG1VIDEO){
                    if (alevel < 128) {
                        put_sbits(&s->pb, 8, level);
                    } else {
                        if (level < 0) {
                            put_bits(&s->pb, 16, 0x8001 + level + 255);
                        } else {
                            put_sbits(&s->pb, 16, level);
                        }
                    }
                }else{
                    put_sbits(&s->pb, 12, level);
                }
            }
            last_non_zero = i;
        }
    }
    /* end of block */
    put_bits(&s->pb, table_vlc[112][1], table_vlc[112][0]);
}

#define OFFSET(x) offsetof(MpegEncContext, x)
#define VE AV_OPT_FLAG_ENCODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM
#define COMMON_OPTS\
        {AV_TIMECODE_OPTION(MpegEncContext, tc_opt_str, \
         AV_OPT_FLAG_ENCODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM)},\
    { "intra_vlc",           "Use MPEG-2 intra VLC table.",       OFFSET(intra_vlc_format),    AV_OPT_TYPE_INT, { 0 }, 0, 1, VE },\
    { "drop_frame_timecode", "Timecode is in drop frame format.", OFFSET(drop_frame_timecode), AV_OPT_TYPE_INT, { 0 }, 0, 1, VE}, \
    { "scan_offset",         "Reserve space for SVCD scan offset user data.", OFFSET(scan_offset), AV_OPT_TYPE_INT, { 0 }, 0, 1, VE },

static const AVOption mpeg1_options[] = {
    COMMON_OPTS
    FF_MPV_COMMON_OPTS
    { NULL },
};

static const AVOption mpeg2_options[] = {
    COMMON_OPTS
    { "non_linear_quant",    "Use nonlinear quantizer.",          OFFSET(q_scale_type),         AV_OPT_TYPE_INT, { 0 }, 0, 1, VE },
    { "alternate_scan",      "Enable alternate scantable.",       OFFSET(alternate_scan),       AV_OPT_TYPE_INT, { 0 }, 0, 1, VE },
    FF_MPV_COMMON_OPTS
    { NULL },
};

#define mpeg12_class(x)\
static const AVClass mpeg## x ##_class = {\
    .class_name   = "mpeg" #x "video encoder",\
    .item_name    = av_default_item_name,\
    .option       = mpeg## x ##_options,\
    .version      = LIBAVUTIL_VERSION_INT,\
};

mpeg12_class(1)
mpeg12_class(2)

AVCodec ff_mpeg1video_encoder = {
    .name                 = "mpeg1video",
    .type                 = AVMEDIA_TYPE_VIDEO,
    .id                   = CODEC_ID_MPEG1VIDEO,
    .priv_data_size       = sizeof(MpegEncContext),
    .init                 = encode_init,
    .encode2              = ff_MPV_encode_picture,
    .close                = ff_MPV_encode_end,
    .supported_framerates = avpriv_frame_rate_tab+1,
    .pix_fmts             = (const enum PixelFormat[]){ PIX_FMT_YUV420P,
                                                        PIX_FMT_NONE },
    .capabilities         = CODEC_CAP_DELAY,
    .long_name            = NULL_IF_CONFIG_SMALL("MPEG-1 video"),
    .priv_class           = &mpeg1_class,
};

AVCodec ff_mpeg2video_encoder = {
    .name                 = "mpeg2video",
    .type                 = AVMEDIA_TYPE_VIDEO,
    .id                   = CODEC_ID_MPEG2VIDEO,
    .priv_data_size       = sizeof(MpegEncContext),
    .init                 = encode_init,
    .encode2              = ff_MPV_encode_picture,
    .close                = ff_MPV_encode_end,
    .supported_framerates = avpriv_frame_rate_tab + 1,
    .pix_fmts             = (const enum PixelFormat[]){
        PIX_FMT_YUV420P, PIX_FMT_YUV422P, PIX_FMT_NONE
    },
    .capabilities         = CODEC_CAP_DELAY | CODEC_CAP_SLICE_THREADS,
    .long_name            = NULL_IF_CONFIG_SMALL("MPEG-2 video"),
    .priv_class           = &mpeg2_class,
};

---